The present invention relates to piston-cylinder actuators, more specially for compressed air operation, having a cylinder structure that is closed at ends thereof, a piston unit able to be reciprocated in the cylinder structure when being acted upon by fluid under pressure, and a central piston rod adapted to be moved out of the cylinder structure to some degree when the actuator performs a working stroke.
Such actuators are used for for a wide range of different purposes in engineering when work has to be performed using a reciprocating piston rod. Dependent on the force to be exerted by the actuator, a variety of different actuators is available with different piston working areas and therefore different overall dimensions. Therefore the producers of such actuators have to manufacture them with different sizes in order to meet current market needs. The need to offer such a variety of different actuators does however necessitate a considerable manufacturing capacity and large stockholding facilities. Furthermore, it is a drawback for the customer that a given actuator is only available with a certain unalterable design and therefore only suitable for limited applications.